Control for printing presses and other motor-driven machines



A AA 4 4111 41 4 Sheets-Sheet l 6 0 0 6 C 5 4 LN 5 1 HQ MMwE MiIH 5 4 1111 AAA 1 H H o ii T n wm wm M IJ. Fww| |=L Z P M F I m m 0 s on". on". 0on. m mm 0 on"? on. =m m o-HHv on".

W. H. ELLIOT ETAL CONTROL FOR PRINTING PRESSES AND OTHER MOTOR DRIVENMACHINES June 29, 1948.

Filed D'ec. 2:5, 1946 June 29, 1948. w. H. ELLIOT ETAL CONTROL FORPRINTING PRESSES AND OTHER MOTOR DRIVEN MACHINES 4 Sheets-Sheet 2 FiledDec. 23, 1946 w I n n n n n n n I.

June 29, 1948- w. H. ELLIOT ETAL CONTROL FOR PRINTING PRESSES AND OTHERMOTOR DRIVEN MACHINES 4 Sheets-Sheet 3 Filed Dec. 23, 1946 June 29,1948. w, ELLIOT ETAL 2,444,186

CONTROL FOR PRINTING PRESSES AND a OTHER MOTOR DRIVEN MACHINES FiledDec. 23, 1946 4 Sheets-Sheet 4 Patented June 29, 1948 CONTROL FORPRINTING PRESSES AND OTHER MOTOR-DRIVEN MACHINES William H. Elliot,Shorewood, and Cyril P. Fold.- hausen, Wauwatosa, Wis., assignors toCutler- Hammer, Inc., Milwaukee, Wis., a corporation of DelawareApplication December 23, 1946, Serial No. 718,074

' 20 Claims. 1

This invention relates to control for printing presses and other motordriven machines.

More particularly the invention relates to controllers for motor drivenmachines comprising units, as for example printing presses comprisingprinting units and folders, having individual motor drives andcommutatable mechanical interconnections to provide for differentgroupings of the units with the units of each group mechanicallyinterconnected to insure operation thereof in unison.

In the copending application of W. H. Elliot,

Serial No. 587,245, filed April 9, 1945, there is disclosed a singlemotor drive for a printing press and control therefor which in part isof the electronic type and which affords press drive by the single motorat the desired running speeds, or alternatively at slow constant speedsuitable for inching and/or threading, and the present invention hasamong its objects to extend such control to motor driven machines of theaforementioned multiunit type having individualized driving motors to becontrolled in difierent groups according to the groupings of the units.

Another object is to minimize the control apparatus individualized toeach of the units and to enable a group of driving motors to becontrolled for slow speed by control means common thereto.

Another object is to provide multiunit control comprising in partelectronic control means, which electronic control means may be commonto all motors of a group of driven units.

Another object is to provide a. printing press system wherein theindividualized controls for the folders comprise all of the slow speedelectronic control apparatus required by the group or groups of pressunits and folders, thus enabling the controls individualized to theprinting units to be reduced to the means for obtaining the desiredrunning speeds.

Another object is to provide a system wherein the control panels-for thefolders may be alike and wherein the simpler control panels for theprinting units may be alike.

Another object is to provide for a multiunit motor driven machinecommutatable control means wherein the circuits requiring commutationfor different groupings of the driven units are simple, and may becontrolled through the medium or" simple and reliable switching means.

Another object is to provide cornmutatable control means of theaforementioned character which additionally provides for braking of thedriven tors.

Another object is to provide commutatable control means for a multiunitdriven machine, which control means includes a set of push buttonswitches for each press unit to effect full control of it and the unitsmechanically interconnected therewith, such full control includingcontrol through the medium of the slow speed control means commonto allof the mechanically interconnected units.

Another object is to afiord the motors of each group selective slowspeeds under the control of the electronic means.

Various other objects and advantages of the invention will hereinafterappear.

The accompanying drawing illustrates schematically and diagrammaticallyone embodiment/of the invention which will now be described, it beingunderstood that the embodiment illustrated is susceptible of variousmodifications without departing from the scope of the appended claims.

In the drawing,

Figure 1 shows schematically a printing press comprising a plurality ofprinting units and folders having individualized single motor drives andalso shows control panels individualized to the press units, togetherwith relay panels for control of pilot motors utilized to operate speedregulating devices on the control panels under the control of pushbutton stations;

Fig. 2 shows diagrammatically power circuits of the several drivingmotors of the press, electronic means to be included in certain of theReferring to Fig. l, the printing press shown thereby comprises printingunits P P P 1? and folders F F The printing units have single motordrives M M M and M individualized thereto, while the folders haveindividualized thereto single motor drives M and M The motors areaxially alined and are adapted to be mechanically connected through acommon shaft ill comprising a plurality of sections and couplingstherefor, preferably mechanical. As is customary, the printing units Pto P and the folders F F are individually connected to sections of shaft18 through bevel gear sets II. The shaft III has interposed betweenmotor M and the bevel gears ll of folder F a clutch l3 and between saidmotor and the bevel gears of printing unit P a clutch M. Similarclutches are interposed between each of motors M M M and M and the twopress units adjacent to each, while a clutch I5 is interposed betweenmotor M and the bevel gears of folder F Thus as will be apparent, thepress units may be interconnected in different groupings. For example,-printing units P and P and folder F may be grouped for drive by motors MM and M while the remaining printing units and folder may be grouped fordrive by motors M M and M Alternatively it will be apparent that allprinting units may be grouped with folder F for drive by motors M NP, MM and M the folder F being disconnected. As will be understood, ,othergroupings may be effected with the number of units shown, whereas thetotal number of units may be increased or decreased as desired.

The motors M to M preferably are alike, and preferably are of thepolyphase induction type. As indicated in Fig. 1, each motor is providedwith an individualized control panel, the control panels C C, C and Cfor motors M M, M and M, respectively, being alike, and the controlpanels C and C for the motors M and M, respectively, being alike butbeing somewhat different from panels C to C". All control panels arealike in having a crosshead type speed regulator 20, such speedregulators preferably being alik and collectively having pilot drivingmotors 2i and 22. Pilot motors 2| and 22 are interconnected by a shaft23 comprising a plurality of sections and mechanical couplings 24 forsaid sections, there being a separate section for each speed regulatorand a bevel gear connection 25 between each speed regulator and itsrespective shaft section. The couplings, as will appear, are ofsuilicient number and are so located as to enable the speed regulatorsand pilot motors to be grouped correspondingly to the groupings of theprinting units and folders of the press. Also all control panels arealike in having two electroresponsive switches 21 and 28 of the triplepole type.

Control panels C and C additionally comprise electronic equipmentincluding electron tubes 3|] and 3i, Fig. l, and other tubes, Fig. 3.Also each such panel comprises two electroresponsive relays 32 and 33associated with tubes 30 and 3| of the respective panel, each such relaybeing of the double throw type. Relay 32 has normally engaged contacts32 to be disengaged when said relay is energized, and normallydisengaged contacts32 to be engaged when said relay is energized, therelay 33 having similar contacts.

Further referring to Fig. 1, relay panels 35 and 36 are provided forcontrol of the pilot motors 2| and 22, respectively, and for control ofother of the aforementioned instrumentalities under the control of pushbutton stations. For simplicity of illustration only three such stations31, 38 and 33 are shown, the stations being alike and comprising stop,inch, on and off push button switches so designated, but as will beunderstood there would ordinarily be one or more push button stationsfor each of the printing units and folders. The, stations 31 and 38 arecoordinated with the folders F and F while station 39 is representativeof the stations individualized to the printing units of the press. Alsoas will be understood, the relay panels 35 and 36 may have permanentelec- 4 V trlcal connections with their respective pilot motors 2| and22, their respective control panels C C and their respective controlstations 31, 38, such connections being represented in Fig. 1 byuninterrupted cables. On the other hand, it will be understood that inview of the aforementioned possible different groupings of the pressunits and control panels the relay panels require changeableinterconnections between one another and between each and all controlpanels C to 0. Likewise th relay panels require changeableinterconnections between each of the same and the push button stationsrepresented by the single station 39. Such changeable interconnectionsare represented by cables comprising section and suitable electricalcouplings 40 for the sections. Of course the couplings 40 may ifpreferred take the form of switches as in Fig. 2. Current for the motorsand all control instrumentalities is supplied from lines L 12,1 and forindication thereof cable connections have been shown as extending fromsaid lines to each of the control panels C to C.

Referring to Fig. 2, it shows diagrammatically the motors M to M as eachhaving a primary for connection to lines L L, L through its respectiveswitch 21 aforementioned and as having secondary connections of whichthose shown for motor M are typical. Motor M is shown as havingresistors r r and r for the different phases of its secondary circuit,which resistors are under the control of its respective speed regulator20 here represented by crosshead and driving screw. Also motor M isshown as having resistors r r 1' for the different phases of itssecondary circuit, which resistors are used in braking only, beingsubject to exclusion by the aforementioned switch 28 of the respectivecontrol panel.

Also Fig, 2 shows the two sets of electronic tubes 30 and 3| of controlpanels C and C, the two sets of relays 32 and 33 of said panels anddouble pole knife switches 50 to 56 providing for different groupings ofthe driving motors with the motors of each group in a parallel relation.More particularly switches 5| to 55 provide for connecting togethersections of a conductor 60, which sections are respectively connected tothe center terminals of the motors M to M and also for connectingtogether sections of a conductor 61 which are respectively connected tothe lowermost terminals of said motors, all of said connectionsextending through the respective switches 21. Switches 50 and 56 controlother connections of the sectional conductors 60 and 6|. With switches50 and 56 closed, conductors 60 and 6| are adapted to be bridged by thenormally closed contacts of relays 32 and 33 of panels Cl and C Alsowith switches 50 and 56 closed conductor 60 forms with conductor 66 aloop having a connection to line L and with relays 33 energized thebridges of conductors 60 and 6| are interrupted, and conductor 6| formswith conductor 62 a loop having a, connection to line L Such connectionsto the supply lines are made through a triple pole knife switch 64,which knife switch connects to line L a conductor 65 which has leads tothe uppermost primary terminals of motors M to M With the switches 50and 56 closed and with the relays 32 energized, but with the relays 33deenergized, the tubes 30, 3! of panels C C have a connection by way ofconductor 62 to line L With all knife switches of Fig. 2 closed allmotors M to M form a single group to be supplied with power from lines LL, L upon closure of switches 21. With relays 32 of panels C and Cdeenergized but with relays 33 of such panels energized the motors wouldbe connected to. the supply lines exclusive of the tubes 30, ll of bothpanels. The common feed wire 6| would be connected' to conductor 62 andhence to line L as above set forth, whereas the common feed wires 60 and65 would be connected to the other two supply lines, as aforedescribed.On the other hand, with relays 32 of panels C energized and relays 33deenergized the two sets of tubes 30, 3| would be included in parallelrelation in the common connection between the lowermost primaryterminals of the motors and line L, the other motor connectionsremaining as aforedescribed. Through th medium of the tubes included inone phase of each motor primary circuit slow speed operation of themotors is obtained, as hereinafter more fully set forth, and for suchslow speed operation the resistors r 1 and r are included in thesecondary circuits of the motors, whereas the switches 28 are energizedto short-circuit resistors 1 r and r Exclusion of the tubes and 3| fromcircuit in the manner aforedescribed provides for operation of themotors at running speeds determinedby adjustment of the resistors r 1'and r by the speed regulators 20, the resistors r 1 r remaining excludedfrom circuit. When the motors are in operation deenergization of allrelays 32, 33 effects through their normally closed contacts bridging offeed wires 60, 6! and hence bridging of two of the primary terminals ofeach motor for single phase braking action under which conditions theresistors r 1 r are included in the secondary connections ofthe motorsby opening of switches 28. Considering a few of the numerous possiblegroupings afforded by the arrangement shown in Fig. 2, closing ofswitches 50, 5|, 52, 56, and 56 with switch 53 -remaining open providesfor placing motors M M M under the control of panel C and motors M M 1,M under the control of panel C, the panels C and ('3 being disconnectedfrom one another by the open switch 53. Alternatively any number of thepress unit motors might be grouped with folder M under the control ofpanel C by closing switch 50 and an additional switch for each of thegrouped press unit motors while leaving switch 56, for example, open todisconnect panel (3' from panel C Similarly the press unit motors mightbe grouped with folder motor M under the control of panel C by closingswitch 56 and an additional switch for each of the grouped press unitmotors while leaving switch 50 open'to disconnect panel C from panel CAssuming closure of all knife switches except 52 or 5% one group ofmotors would comprise one folder motor and one printing unit motor,whereas the other group would comprise one folder motor and threeprinting unit motors, one group being under the control of panel C andthe other under the control of panel C.

Referring to Fig. 3, it shows in further detail,

but without illustration of relays 32 and 33 of Figs. 1 and 2,electronic control means for the folder panels i3 and C, such controlmeans being similar to control means disclosed in the aforementionedcopending application. Fig. 3 shows control means for panel C only, itbeing understood that such control means would be duplicated for panel Cand for each additional folder panel if desired. Inasmuch as Fig. 3shows control for panel C the one motor shown in this figure isdesignated M the showing of circuits for this'motor being limited tothose of its primary. As heretofore set forth, the electronic .6 vcontrol means will influence not only its respective motor but allmotors grouped therewith.

Briefly described, the control shown in Fig. 3 comprises theaforementioned tubes 30 and 3! to be included in circuit between themotor or motors and line L and to be controlled for slow constant speedmotor operation, as for inching or threading. Tubes 30 and 3| are shownas of the ignitron type, and as will be apparent said tubes areinterconnected for discharge alternately to pass both halt waves of analternating current. Such tubes have ignition electrodes 30 and 3 I,respectively, which are respectively under the influence o1 thyratrontubes 10 and ll, each of said ignition electrodes being connectedthrough a suitable resistor to the cathode of its respective thyratrontube. The anodes of tubes 3|, l0 and II are all connected to line L asis also the cathode of tube 30, whereas the anode of tube 30 and thecathode of tube 3| have connections leading to the lowermost terminal ofmotor M through contacts of switch 21. The cathodes of tubes 10 and IIare respectively connected to the upper terminals of secondary windingsl2 and 13 of a transformer T and the control electrodes of said tubesare respectively connected to the lower terminals of said transformerwindings through suitable resistors, a capacitor 15 being preferablyconnected across the leads tothe cathode and control anode of each ofsaid thyratron tubes. The transformer T has a primary winding 14 whichhas one terminal connected to the center tap of an impedance 16connected across lines U, L and which has its other terminal connectedto line L through the winding 11 of a saturable reactor 18, the lastmentioned terminal of winding 74 also having a connection through asuitable resistor to line L This reactor has a saturating winding 79which is connected across a battery 80 through an electron tubes! and asuitable resistor. Tube 8! has a control electrode connected to theanode of a tube 82. Tube 82 has its anode connected through a suitableresistor to the positive side of a circuit supplied bya battery 83 andhas its cathode connected to the movable contact of a voltage dividingresistor 84 connected across battery 83. The control electrode of tube82 is connected through a suitable resistor to the anode of a tube 85.Tube 85 has its cathode connected to the negative side of the circuitsupplied by battery 83 and has its anode connected to the positive sideof said circuit. Also connected across the last mentioned circuit is avoltage dividing resistor tli which has its adjustable contact connectedby down contacts of a relay 8% to the positive side of the armature of atachometer generator 8i coupled to motor M to be driven thereby, thenegative side of said generator armature being connected through a suitable resistor to the control electrode of tube 85. A second voltagedividing resistor 89 in parallel to resistor 86 is adapted to have itsmovable contact included in circuit in lieu of the contact of resistor88 upon response of relay 88.

With the control just described the tubes 30 and 3i in starting of themotor M from rest will be conducting during substantially their entirerespective half cycles, but as the motor sets in motion the tachometergenerator the duration of the periods of conduction of said tubes willbe decreased, and with the contact of voltage dividing resistor 86properly adjusted the periods of conduction of said tubes may be sorestricted as to hold the motor to a very slow speed. As the motorsgrouped with motor M are dependent upon the same source of power theirspeed will -likewise be restricted.

Briefly describing the operation of the control of Fig. 3, conduction ofthe ignitron tubes 38 and 31 is initiated at the moment when theirrespective thyratron tubes 18 and 1| become conducting and when startingthe motor M from rest the thyratron tubes will become conducting at thebeginning of their respective positive half cycles. This is due to thefact that the current passing through the saturating winding 19 is thenat a maximum, with the result that the phase angle between the voltageimpressed n tubes 18 and 1| and the voltage induced in windings 12 and13 due to the voltage obtaining in winding 14 is a minimum. The voltageimpressed on the control electrode of tube 85 by the voltage divider 88is of sufliciently high positive value with respect to the cathode oftube 85 to render said tube highly conducting when no opposing voltageis supplied through the tachometer generator 81 as when the motor M isat standstill. The high current flowing through tube 85 produces arelatively high voltage drop through the resistor in series therewith sothat the tube 82 by virtue of its low grid potential has relatively lowconductivity which in turn produces a relatively low potential dropthrough the resistor in series therewith, wherefore the controlelectrode of tube BI is only slightly negative with respect to itscathode, and this in turn causes a relatively high current to flow fromthe positive terminal of battery 88 through the saturating winding 19and tube 8| to the negative terminal of said battery. Thus the reactoris highly saturated and the current through the winding 11 is large,thereby affording a voltage in the winding 14 of transformer T andcorresponding voltages in the windings 12 and 13 which are substantiallyin phase with the voltage impressed upon tubes 18 and H. As the motorstarts, the tachometer generator supplies a supplemental voltage to thecontrol electrode of tube 85 which is opposed to the voltage supplied bythe voltage dividing resistor 86, with the result that with increase inspeed of the motor the tube 85 becomes less conducting, thus increasingthe conduction of tube 82, which in turn decreases the conduction oftube 8i, and thereby decreases the current in saturating winding 19.This decreases the current in the reactor winding 11, which results inincrease of the retardation of the phase angle of the voltages in thewindings of transformer T with respect to the voltage of lines L L L andthereby retards the moment of ignition during the respective half cyclesof tubes 18 and H, and this through the tubes 38 and 3| reduces theeffective current supplied to one terminal of each of the grouped motorsso as to maintain the speed thereof at a low constant value determinedby the adjustment of the contact of voltage dividing resistor 88.

circuits being under the control of the push button stations.

Briefly set forth, Fig. 4 shows contacts of one of the speed regulators28 and one of the pilot motors 2i of Fig. 1, windings for switches 21,18

of Fig. l, relays 32, 33 of Fig. 1, relay 88 of Fig. 3, an inch relay98, an on relay 9|, an of! relay 92, astop relay 93, a timing relay 94,and an additional relay 95. The push button switches shown in thisfigure comprise an inch switch 98, an on switch 91, an oil switch 98 anda stop switch 98. The pilot motor 2| is shown as having field winding-sf and f to be energized selectively for reverse operations of saidmotor, which as will be understood from the showing of Fig. 1 effectsreverse operations of the crosshead of speed regulator 28. While theresistors r 1", r of the speed regulator 28 are not shown in Fig. 4 itwill be understood that they are arranged to be varied gradually as thecrosshead moves along the elongated contacts shown in Fig. 4.

While the control shown in Fig. 4 would in practice ordinarily besupplemented in various respects, including provision of signalingmeans, means to efiect step by step operation of the crosshead of thespeed regulator, etc., the showing of Fig. 4 will suflice to afford anunder-standing of the control of the apparatus hereinbefore described,it being borne in mind that as indicated by the dotted line showing inFig. 4 of windings of switches 21 and 28, the Fig. 4 control iseflfective in respect of a single drive or a plurality of drives ifgrouped together.

As will be apparent, selective predetermined slow speeds may be providedfor in various ways as through the medium of the additional voltagedividing resistor 89. The latter resistor may obviously be designed andadjusted for a higher slow speed when its contact is included in circuitin lieu of the contact of resistor 88, and obviously more than twospeeds might be provided for in a similar way.

Referring to Fig. 4, it shows control circuits for the electroresponsiveswitches and relays hereinbefore specified and for additionalelectroresponsive relays hereinafter enumerated, such Assuming closureof the inch push button switch 96, it connects winding 98" across linesU, L through an on limit switch I88, which as will be understood is anormally closed switch opened by the speed regulator 20 in its fullspeed position. Winding being thus energized, the inch relay respondsand its contacts. iili connect across lines L and L through a suitableresistor i8! winding 93 of the stop relay. The stop relay uponresponding engages its contacts 93 to establish for itself a maintainingcircuit independent of the inch relay and by engagement of its contacts93 completes an across-the-line energizing circuit for one or moreresistance controlling switches 28 of Fig. 1 according to the groupingof the press units and controls thereof. Also the stop relay uponresponding engages its contacts 93 to establish for certain windingshereinafter referred to a connection to line L. The inch relay inaddition to so energizing the stop relay completes by its contacts 90 acircuit from line L through contacts of the speed regulator when in theposition shown, to and through the winding of one of the relays 32 ofFigs. 1 and 2, and thence through contacts 98 of the stop relay to lineL Relay 32 thus responds to include in circuit in the manner previouslyexplained the ignitron tubes of one of the electronic controls.Additionally the inch relay in responding engages its contacts 98 toconnect across lines L L winding 94 of timing relay 94, and the latterrelay by engaging its contacts 94 establishes an across-the-lineenergizing circuit for one or more of the switches 21 of Fig. 1according to the grouping of the press units. Thus the driving motors ofthe press units grouped together will be connected to the power linesand will be held to slow speed by the electronic control, as heretoforeexplained. On the other hand, the motor or motors will be disconnectedfrom circuit immediately upon release of the inch push button switch 96.Release of push 9 button switch 96 eifects release of the inch relay,which in turn deenergizes relay 32, and this, as hereinbefore set forth,interrupts the motor connections to one line of the supply circuit.Stopping of the motor or motors results even though vthe switch orswitches 21 remain closed, and

provision is made whereby releaseof switches 21! is delayed for atransient period to permit of a further inching operation by merelyreenergizing the relay 32. As shown, this is accomplished by providingwinding 94 of the timing relay with a shunt including a resistor I02 anda capacitor I03 and by including in series with said winding a rectifierI04. With this arrangement the shunt for winding 94 affords the relay ina well known manner a time element incident to release and pendingrelease of relay 94 its contact M maintain the energizing circuit ofswitch or switches tinued by hold-down of the push button 91 said relaywill effect operation of motor 2| to advance the crosshead of the speedregulator 20 to the right. More particularly, the relay 9i through itscontacts 9| completes a circuit from line L to and through the nowclosed contacts 21. Obviously if another inching operation is notinitiated within the period required for release of relay 84 said relayreleases to deenergize the switch or switches 21 for completedisconnection of the motor or motors from the supply circuit. With thecircuit arrangement illustrated the stop relay 93 would remain energizedafter termination 'of inching, subject to deenergization by closing ofthe push button switch 99. This switch, as will be apparent, aiiordsshortcircuiting of the winding 93 at will for release of said relay.

Assuming now that the stop relay is open and that the on push buttonswitch 9'! be closed, said switch will connect across lines L L throughthe on limit switch 600, the winding di of on relay Bi. Relay 8! uponresponding engages its contacts 9| to parallel the maintaining contacts93 of the stop relay, thus energizing said relay which again maintainsitself through its contacts 93 Stop relay 93 again engages contacts 93to energize the switch or switches 23 and by engaging its contacts 83connects across lines L L winding 9-5 of relay 95 through now closedcontacts 3i of off relay 9i. Relay 95 thus responds and by engaging itscontacts 95' estah suming release of the on push button switch followingstarting, the controlled motors would, of course, continue to operate atslow speed as for threading, and as heretofore explained the electronicmeans may be supplemented to afford difierent slowspeeds to be selectedat will. As

' shown, the speed regulator has several positions in which the circuitof winding 32 is maintained energized and such positions-of the speedregulator may be utilized to adjust the electronic means for itsdifferent predetermined slow speeds. As shown in Fig. 4, the speedregulator all when advanced to the second pair of contact buttonscompletes an across-the-line circuit for the winding of relay 88, whichrelay as shown in Fig. 3 provides for an adjustment of the slow speedafforded by the electronic means.

The on relay 9| is energized only so long as the on push button switch91 is held closed and for continuous slow speed operation relay 9! wouldbe energized only momentarily. On the other hand, if energization ofrelay 9! is con- 95 of relay 95, to and through the winding f andarmaturea of motor 2| to line L. Then if the crosshead be advanced tothe right beyond the contact buttons to which the winding of relay 32 isconnected, said relay is deenergized to disconnect from circuit theelectronic control,

whereas the winding of relay 33 of Figs. 1 and 2 is energized toestablish a direct connection between the controlled motors and line L,as heretofore explained. The energizing circuit of relay 33 extends fromline L through the speed regulator to and through the winding of saidrelay and through contacts 93 or the stop relay to line L. Thecontrolled motor or motors will then operate at an increased speeddetermined by the adjustment of the motor secondary resistors 1 r", 1 Bycontinued depression of the on push button switch 9?, relay 9! may bemaintained energized for operation 01 the speed regulator to cut out anyamount or all of the motor secondary resistors r r 1 according to themotor speed desired. When the speed regulator reaches full speedposition it opens on limit switch Hill which deenergizes the on relay.

Speed reduction following establishment of a high speed may be obtainedat any time by closing the ofi push button switch 9$ which completescircuit from line L through contacts 33 of relay 33, to and through thewinding 52 of off relay 92, to and through an oil limit switch 095 toline L said limit switch being one which is opened in the off positionof the speed regulator. sponse of relay 92 which through its contacts92* completes for motor 2!. a circuit including its reverse fieldwinding ,1 whereby the, motor drives the crosshead to the left. Thisreduces the motor speed to a value determined by the length of time pushbutton switch 98 is held depressed, said switch when releaseddeenergizing relay 92 to arrest the speed regulator.

When the motor is running stopping may be eifected at any time bydepressing the push button switch 99 which deenergizes the stop relay,as aforedescribed. Deenergization of the stop relay deenergizes theotherrelays including re- What we claim as new and desire to secure byLetters Patent is: I

1. In combination, a plurality of like polyphase induction motorsindividually to drive units of a machine, interconnections between saidmotors to restrict the same to operation as a group, slow speed controlmeans for said motors comprising means driven by certain of the groupedmotors to produce voltage variable with the speed thereof and comprisingmeans to effect voltage unbalance of the primaries of saidmotorsvariable under the influence of such variable voltage, and

Energization of winding 92 effects recontrol means optionally to eflectoperation of the grouped motors at any of a number of running speeds.

2. In combination, a plurality of like polyphase induction motorsindividually to drive units of a machine, interconnections between saidmotors restricting the same to operation as a group, means driven bycertain of the grouped motors to produce voltage variable with the speedthereof, and slow speed control means for the grouped motors comprisingelectronic means under the influence of said variable voltage andefl'cctive for varying voltage unbalance of the primaries of the groupedmotors, and control means optionally to effect operation of the groupedmotors at any of a number of running speeds.

3. In combination, a plurality of like polyphase induction motorsindividually to drive units of a machine, interconnections between saidmotors restricting the same to operation as a group, means driven by oneof said motors to produce voltage variable with the speed thereof, andslow speed control means for said motors comprising means under theinfluence of such voltage and being common to said one motor and themotors grouped therewith to effect varying voltage unbalance of theprimaries of such grouped motors.

4. In combination, a plurality of like polyphase induction motorsindividually to drive units of a machine, a polyphase supply circuit,means to connect the primaries of said motors in parallel to said supplycircuit, means driven by one of said motors to produce voltage variablewith the speed thereof, and control means for said motors comprisingelectronic means under the influence of said variable voltage andfurther comprising means for including part of said electronic means incircuit between one line of said supply circuit and one primary terminalof each of said parallel connected motors for slow speed and forexcluding the same from circuit for running speeds.

5. In combination, a plurality of polyphase induction motorsindividually to drive units of a machine, a polyphase supply circuit,means to mechanically interconnct with a given one of said motors avarying number of the other of said motors, means driven by said onemotor to produce voltage variable with the speed thereof, means underthe influence of said variable voltage to be used to effect voltageunbalance of the primaries of the interconnected motors and means toconnect the primaries of such interconnected motors to said powercircuit in parallel, selectively with or without inclusion of the thirdmentioned means in circuit between one primary terminal of each of saidparallel connected motors and one line of said supply circuit.

6. In combination, a plurality of induction motors individually to driveunits of a machine, a

polyphase supply circuit, means to mechanically interconnect with agiven one of said motors a varying number of the other of said motors,

means driven by said one motor to produce voltage variable with thespeed thereof, electronic means under the influence of said variablevoltage and means to connect the, primaries of such interconnectedmotors to said power circuit in parallel. selectively with or withoutinclusion of part of said electronic means between one primary terminalof each of said parallel connected motors and one line of said supplycircult.

'7. In combination, a plurality of three phase induction motorsindividually to drive units of a machine, a polyphase supply circuit,interconnections between said motors to restrict the same to operationas a group, means to connect said motors to said supply circuit'and toeil'ect selectively slow or high speed operation thereof, said meansconnecting the terminals of said motors in parallel to said supplycircuit and providing for disconnecting one primary terminal of each ofsaid motors from said supply circuit while maintaining connectionsbetween the other primary terminals of each motor and said supplycircuit, and means which for braking while said motors remain soconnected bridges the disconnected terminal of each motor with one ofthe other terminals thereof.

8. In combination, a plurality of three phase induction motorsindividually to drive units of a machine, a polyphase supply circuit,interconnections between said motors to restrict the same to operationas a group, means to connect said motors to said supply circuit and toeiiect selectively slow or high speed operation thereof, said meansconnecting the primaries of said motors in parallel to said supplycircuit and providing for disconnecting one primary terminal of each ofsaid motors from said supply circuit while maintaining connectionsbetween the other primary terminals of each motor and said supplycircuit, and means to effect single phase braking action by said motorswhile remaining so connected, the last mentioned means including meansto bridge the disconnected terminal of each motor with one of the otherterminals thereof and also including means to increase by a given amountthe resistance of the secondary circuit of each motor.

9. In combination, a plurality of three phase induction motorsindividually to drive units of a machine, a three phase supply circuit,interconnections between said motors to restrict the same to operationas a group, means to connect said motors to said supply circuit and toeffect selectively slow or high speed operation thereof, said meansconnecting the primaries of said motors in parallel to said supplycircuit and providing for disconnecting one primary terminal of eachmotor from said supply circuit while maintaining connections between theother primary terminals of each motor and said supply circuit, and meanswhich for braking while said motors remain so connected bridges thedisconnected terminal of each motor with one of the other terminalsthereof, said interconnections and said means being commutatable forrendering certain of said motors free of the others and of the controlof the latter.

10. In combination, a plurality of three phase induction motorsindividually to drive units of a machine, a three phase supply circuit,interconnections between said motors to restrict the same to operationas a group, means to connect said motors to said supply circuit and toeffect selectively slow or high speed operation thereof, said meansconnecting the primaries of said motors in parallel to said supplycircuit and providing for disconnecting one primary terminal of eachmotor from said supply circuit while maintaining connections between theother primary terminals of each motor and said supply circuit, and meanswhich for braking while said motors remain so connected bridges thedisconnected terminal of each motor with one of the other terminalsthereof, said interconnections and said means being commutatable todivide said motors into a plurality of groups independently controllableor being controllable in the manner set forth.

11. In combination, a three phase induction motor, a three phase supplycircuit therefor, means to connect all the primary terminals of saidmotor to their respective lines of said supply circuit for poweroperation and in stopping said motor first disconnecting one terminalthereof and then disconnecting its remaining terminals, said meansincluding means affording a given time interval between suchdisconnecting steps, and means to bridge the disconnected terminal withone of the other terminals throughout such time interval.

12. In combination, a three phase induction motor, a three phase supplycircuit therefor, means to connect all the primary terminals of saidmotor to their respective lines of said supply circuit for poweroperation and in stopping said motor first disconnecting one terminalthereof and increasing the resistance of the secondary circuit of saidmotor and then disconnecting the remainder of said motor terminals, saidmeans including means affording a given time interval between suchdisconnecting steps and means to bridge the disconnected terminal withone of the other terminals throughout such time interval.

13. In combination, a three phase induction motor, a three phase supplycircuit, means controlling the connections between the primary terminals of said motor and said supply circuit and comprising two switchesto be operated selectively to establish difierent circuits between agiven primary terminal and said supply circuit, said switches when intheir respective normal position interrupting both or said circuits,means included in one of said circuits'to efiect voltage unbalance ofthe motor primary, the other of said circuits being a direct connectionfrom said given terminal to said supply circuit,'and a bridging circuitfor said given terminal and another of said terminals completed by saidswitches jointly when in their respective normal positions.

14. In combination, a plurality of three phase induction motors, a threephase supply circuit, means to connect in parallel to said supplycircuit the primary terminals of a varying number of said motors, saidmeans comprising two selectively operable switches for establishingselectively different circuits between a given terminal of each of saidmotors and one line of said supply circuit, one of said circuitsconstituting a direct connection,- means included in the other of saidcircuits to effect voltage unbalance of the primaries of said motors,said switches when in their respective normal positions interruptingboth of the'aforementioned circuits and circuit connections establishedby said two switches when in their respective normal positions, whichlast named circuit bridges said given terminal of each motor with asecond terminal thereof.

15. In combination, a plurality of three phase induction motors, a threephase supply circuit, means to connect in parallel to said supplycircuit the primary terminals of a varying number of said motors, saidmeans comprising two selectively operable switches for establishingselectively different circuits between a given terminal of each of saidmotors and one line of said supply circuit, one of said'circuitsconstituting a direct connection, means included in the other of saidcircuits to efiect unbalance of the primaries of said motors, saidswitches when in their respective normal positions interrupting both ofthe aforementioned circuits and circuit connections established bysaidtwo switches when in their respective normal positions, which lastnamed circuit bridges said given terminal or each motor with a secondterminal thereof, said first mentioned means in eil'ecting disconnectionof said motors for stopping first effecting disconnection of said giventerminal of each motor and then efiectlng disconnection of the otherterminals thereof and comprising means insuring a Elven time intervalbetween such disconnecting steps.

16. In combination, a plurality of printing units, a plurality offolders, commutatable mechanical couplings for said units and folders,in-

dividual driving motors of the polyphase slip ring type for said unitsand folders, a polyphase supply circuit and control means for saidmotors commutatable for group control of said motors according to theoommutations of said mechanical couplings, said control means comprisingin association with each folder, means to establish for the respectivefolder motor and the unit motor or motors grouped therewith slow speedprimary connections to said supply circuit.

17. In combination, a plurality of printing units, a plurality offolders, commutatable mechanical couplings for said units and folders,indlvidual driving motors of the polyphase slip ring type for said unitsand folders, a polyphase supp y circuit and control means for saidmotors commutatable for group control of said motors according to theeommutations of said mechanical couplings, said control means comprisingin association with each folder, means to establish for the respectivefolder motor and the unit motor or motors grouped therewith slow speedprimary connections to said supply circuit including means to effectvoltage unbalance of the motor primaries.

18. In combination, a plurality of printing units, a plurality offolders, commutatable mechanical couplings for said units and folders,individual driving motors of the polyphase slip ring type for said unitsand folders, a polyphase supply circuit and control means for saidmotors commutatable for group control of said motors according to thecommutations of said mechanical couplings, said control means comprisingin association with each folder means to establish for the respectivefolder motor and the unit motor or motors grouped therewith slow speedor high speed primary connections to said supply circuit, the slow speedconnections including means to effect voltage unbalance of the motorprimary, and said means associated with each folder further comprisingmeans to establish for the grouped motors primary connections to theline for single phase braking action of said motors.

19, In combination, an induction motor, an alternating current supplycircuit, means for inclusion in circuit between the primary of saidmotor and said supply circuit for limiting said motor to inching speed,a main switch and a slow speed switch for jointly completing the motorprimary circuit inclusive of said means, the latter switch beingoperable to stop said motor while said main switch remains closed,control means for said switches comprising to eifect closing and openingthereof an inch switch, and further comprising a time element device todelay opening of said main switch in response to said inch switch,thereby to provide a period in which another inching operation may beinitiated by reclosure of said slow speed switch, and means which to- Igether with said main switch provide selectively for power operation ofsaid motor with said speed limiting means excluded from circuit or forconnections rendering said motor self-braking for a transient perioddetermined by said time element device.

20. In combination, an induction motor, an alternating current supplycircuit, means for inclusion in circuit between the primary or saidmotor and said supply circuit for limiting said motor to inching speed,a main switch and a slow speed switch for jointly completing the motorprimary circuit inclusive of said means, the latter switch beingoperable to stop said motor while said main switch remains closed,control means for said switches comprising to eflect closing and openingthereof an inch switch and further comprising a time element device todelay opening ofi said main switch in response to said inch switch,

thereby to provide a period in which another inching operation may beinitiated by reclosure of said slow speed switch, and means whichtogether with said main switch provide selectively for power operationof said motor with said speed'limiting means excluded from circuit orfor braking connections tor the primary of said motor, said brak-

